ref (C# Reference)
- Passing an argument by reference. When used in a method's parameter list, the ref keyword indicates that an argument is passed by reference, not by value.
- Passing an argument by reference: An example. ...
- Reference return values. ...
- Ref locals. ...
- Ref readonly locals. ...
- A ref returns and ref locals example. ...
- C# language specification. ...
What is the effect of ref keyword in Java?
"The ref keyword causes an argument to be passed by reference, not by value. The effect of passing by reference is that any change to the parameter in the called method is reflected in the calling method."
What is the use of Refref in C?
ref in C#. The ref keyword in C# is used for passing or returning references of values to or from Methods. Basically, it means that any change made to a value that is passed by reference will reflect this change since you are modifying the value at the address and not just the value.
Why ref keyword is used to pass parameter in a method?
The reason behind is that the use of ref keyword causes the parameter to be passed by reference and not by actual value. In other words, the actual parameter value was shared with the method due to use of ref keyword. So any changes in the value of parameter inside the method, updated the original value as well.
What is the use of the out keyword in C?
The out is a keyword in C# which is used for the passing the arguments to methods as a reference type. It is generally used when a method returns multiple values.
Why do we use ref and out in C#?
ref is used to state that the parameter passed may be modified by the method. in is used to state that the parameter passed cannot be modified by the method. out is used to state that the parameter passed must be modified by the method.
What does REF do in C sharp?
The ref keyword in C# is used for passing or returning references of values to or from Methods. Basically, it means that any change made to a value that is passed by reference will reflect this change since you are modifying the value at the address and not just the value.
What is difference between ref and out keyword?
out keyword is used to pass arguments to method as a reference type and is primary used when a method has to return multiple values. ref keyword is also used to pass arguments to method as reference type and is used when existing variable is to be modified in a method.
What is a ref in programming?
In computer programming, a reference is a value that enables a program to indirectly access a particular data, such as a variable's value or a record, in the computer's memory or in some other storage device. The reference is said to refer to the datum, and accessing the datum is called dereferencing the reference.
Why do we use ref?
The ref keyword indicates that a value is passed by reference. It is used in four different contexts: In a method signature and in a method call, to pass an argument to a method by reference.
What is reference type in C#?
Variables of reference types store references to their data (objects), while variables of value types directly contain their data. With reference types, two variables can reference the same object; therefore, operations on one variable can affect the object referenced by the other variable.
Can we use ref and out in method overloading?
Both ref and out cannot be used in method overloading simultaneously. However, ref and out are treated differently at run-time but they are treated same at compile time (CLR doesn't differentiates between the two while it created IL for ref and out).
What is the difference between VAR and dynamic?
dynamic variables can be used to create properties and return values from a function. var variables cannot be used for property or return values from a function. They can only be used as local variable in a function.
What is ref and out?
Ref and out keywords in C# are used to pass arguments within a method or function. Both indicate that an argument/parameter is passed by reference. By default parameters are passed to a method by value. By using these keywords (ref and out) we can pass a parameter by reference.
Why are references better than pointers?
References are used to refer an existing variable in another name whereas pointers are used to store address of variable. References cannot have a null value assigned but pointer can. A reference variable can be referenced by pass by value whereas a pointer can be referenced but pass by reference.
What are examples of references?
References: Common Reference List ExamplesArticle (With DOI)Article (Without DOI)Book.Chapter in an Edited Book.Dissertations or Theses.Legal Material.Magazine Article.Newspaper Article.More items...
What is a ref struct?
What is a ref struct? Well, a ref struct is basically a struct that can only live on the stack. Now a common misconception is that since classes are reference types, those live on the heap and structs are value types and those live on the stack.
Does C# pass by reference by default?
Passing Reference-Type Variables by Reference By default, C# does not allow you to choose whether to pass each argument by value or by reference. Value types are passed by value. Objects are not passed to methods; rather, references to objects are passed—the references themselves are passed by value.
What does ref mean in a text?
The ref keyword indicates that a value is passed by reference. It is used in four different contexts:
What does ref mean in a parameter list?
When used in a method's parameter list, the ref keyword indicates that an argument is passed by reference, not by value. The ref keyword makes the formal parameter an alias for the argument, which must be a variable. In other words, any operation on the parameter is made on the argument.
When the caller stores the value returned by the GetBookByTitle method as a ref local,?
When the caller stores the value returned by the GetBookByTitle method as a ref local, changes that the caller makes to the return value are reflected in the BookCollection object, as the following example shows.
What is a ref local variable?
A ref local variable is used to refer to values returned using return ref. A ref local variable cannot be initialized to a non-ref return value. In other words, the right-hand side of the initialization must be a reference. Any modifications to the value of the ref local are reflected in the state of the object whose method returned the value by reference.
What is a ref return?
Reference return values (or ref returns) are values that a method returns by reference to the caller. That is, the caller can modify the value returned by a method, and that change is reflected in the state of the object in the calling method.
What does the caller's local variable refer to when the method returns?
In that case, the caller's local variable or the array element refers to the new object when the method returns.
When to use ref or out?
The ref keyword cannot be used on the first argument of an extension method when the argument is not a struct, or a generic type not constrained to be a struct. The in keyword cannot be used unless the first argument is a struct.
What does ref mean in MSDN?
As per MSDN, ref means: "The ref keyword causes an argument to be passed by reference, not by value. The effect of passing by reference is that any change to the parameter in the called method is reflected in the calling method.".
Why do values change after a method is executed?
The reason being, this time we shared the actual pointer with the method and not it's copy. So changes in the pointer (by the re-initialization of TestClass inside the method), updated the original pointer (testClass instance in Main method). So new values were printed after method execution. This is what msdn says i.e. The ref keyword causes an argument to be passed by reference, not by value. The effect of passing by reference is that any change to the parameter in the called method is reflected in the calling method
What is ref keyword?
The ref keyword allows you to change the value of a parameter. The method being called can be an intermediate link in the calling chain. A method using the out keyword can only be used at the beginning of a calling chain.
When we pass the value while calling the method prefixed by the out keyword, it treats it entirely different like we are?
When we pass the value while calling the method prefixed by the out keyword, it treats it entirely different like we are not passing it to the method. Instead we are actually collecting (outing) the value of the out variable from the definition section of the method to the method out variable parameter where we are calling that method.
Why is C# code incorrect?
Because the C# language assigns different definite assignment rules to these different parameter passing modes, these common coding errors are caught by the compiler as being incorrect C# code.
Does calling code need to initialize passed arguments?
While using keyword ref, calling code needs to initialize passed arguments, but with keyword out we need not do so.
When do you specify the ref keyword?
We must specify the ref keyword when passing to the method. Otherwise, it will give a compile-time error.
What is ref and out in C#?
C# includes ref and out are keywords, which help us to pass the value type variables to another function by the reference.
What is the difference between value type and reference type in C#?
C# supports value type and reference type data types. By default, the value type variable is passed by value, and the reference type variable is passed by reference from one method to another method in C# .
Is ref and out the same?
Both ref and out are treated the same as compile-time but different at runtime. We cannot define an overloaded method that differs only on 'ref' and 'out' parameter. The following will give a compiler error.
Can you include other parameters in a ref parameter?
The method can include other parameters with the ref parameter, as shown below.
What is ref in C#?
The ref is a keyword in C# which is used for the passing the arguments by a reference. Or we can say that if any changes made in this argument in the method will reflect in that variable when the control return to the calling method. The ref parameter does not pass the property.
Is it necessary to initialize a parameter before it passes to out?
It is not necessary to initialize parameters before it pass to out. It is not necessary to initialize the value of a parameter before returning to the calling method. It is necessary to initialize the value of a parameter before returning to the calling method.
Is ref and out the same at compile time?
Note: Both ref and out parameter treated same at compile-time but different at run-time.
